Bluetooth wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. The key features of Bluetooth technology are robustness, low power, and low cost. The Bluetooth specification defines a uniform structure for a wide range of devices to connect and communicate with each other.
Bluetooth solutions are increasingly being adopted for mobile phones and for other consumer electronic products. Bluetooth implementations include a Bluetooth protocol stack including an application layer down to low-level radio link management functions. Typically, a host chip (e.g., a mobile phone baseband chip) executes the portions of the Bluetooth protocol stack near the application layer, and a separate Bluetooth transceiver chip, which contains the Bluetooth radio interface, executes the portions of the Bluetooth protocol stack dealing with link management and control. Communications between the host chip and the Bluetooth transceiver chip are typically performed according to an interface defined as an option in the Bluetooth specification. The Bluetooth specification specifies a logical host controller interface (HCI) for commands and events and a transport layer for the physical transport.
The Bluetooth protocol stack on the Bluetooth transceiver chip typically includes the transport layer, the HCI for commands and events layer, the link manager layer, the link controller layer, and the baseband firmware layer. The Bluetooth protocol stack on the Bluetooth transceiver chip is typically stored in a read-only memory (ROM) of the Bluetooth transceiver chip. A random access memory (RAM) of the Bluetooth transceiver chip typically stores Bluetooth user payload buffers received from the host before they are transmitted over an air link. The RAM also stores payload buffers received over an air link before they are transported to the host over the Bluetooth transport layer. The on-chip RAM and ROM of the Bluetooth transceiver chip are significant contributors to the cost of the system.
For these and other reasons, there is a need for the present invention.